Records of Natural Products Articles

 Phakellistatin 15 (1) is a cyclic octapeptide, containing three proline moieties, all in the trans form. It is a constituent of South China Sea sponge Phakella fusca and reported to have antitumor activity. This study describes the first solid-phase total synthesis of peptide 1 by using Kenner's N-acyl sulfonamide "safety-catch" linker. The structural analysis of peptide 1 was performed by mass, NMR and CD studies. The spectral data of synthetic peptide 1 was found to be identical to that reported for natural peptide. However, the synthetic peptide was found to be inactive on human glioblastoma (U-87), pancreatic cancer (PSN-1) and human non-small cell lung cancer (NCI-H460) cells.

The relationship between food and health has become increasingly significant as consumers now demand healthy, tasty and natural foods which perform a useful function in the body. In Turkey, rose hip (Rosa canina L.) is in popular use in foodstuffs such as marmalade, pestil (a traditional Turkish sweet) and syrup or in traditional medicine, mainly as herbal tea. The composition, total antioxidant capacity (TAC) and total phenolic content (TPC) of volatiles of rose hip samples were compared in relation to their stage of maturity and collection location. Rose hip fruit and seed were analyzed using a direct thermal desorption technique coupled with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GCxGC-TOF/MS). The major components found in the volatile fraction released on extraction were free fatty acids. The various stages of maturity of rose hips (green, light yellow, yellow, orange and red coloured) and the place of collection (Istanbul, Mersin, York) resulted in some changes in volatile compound speciation, in TAC and TPC levels. Various extraction methods were compared; methanol extraction, traditional hot water infusion and boiling in water. Boiling in water for ten minutes was the method which demonstrated the highest extraction efficiency. TAC and TPC were determined using different electron transfer−based assays; the Cerium (IV) ions reducing antioxidant capacity, Cupric Reducing Antioxidant Capacity and Folin-Ciocalteu methods. The highest TAC and TPC were found in the red coloured (fully ripe) rose hip fruit, suggesting that colour is a suitable indicator for optimal harvesting time.

The hydrodistillated essential oils and hexane extracts of two spice plants, Cymbocarpum erythraeum (DC.) Boiss. and Echinophora tenuifolia L. were analyzed by GC and GC-MS. C. erythraeum oil is rich in aliphatic aldehydes, alcohols and acids and (E)-2-decenal (26.1%), (E)-2-decen-1-ol (15.7%), (E)-2-dodecenal (13.2%) and decanal (7.8%) were the predominant components. However, ethyl palmitate (16.4%), 2-decenoic acid (14.1%) and (E)-2-dodecenal (5.2%) were the major components of the hexane extract of C. erythraeum. E. tenuifolia oil contained mainly methyl eugenol (53.0%), p-cymene (17.0%) and α-phellandrene (13.2%). The hexane extract displayed a different chemical composition, and n-tricosane (75.0%) and n-pentacosane (7.6%) were found to be the major compounds. The oils showed antimicrobial activity against various microorganisms and they were more active against the tested fungal species as compared with bacteria. The growths of important food-borne pathogens, Salmonella, Staphylococcus aureus and Escherichia coli were also inhibited by the oils. However, hexane extract of C. erythraeum was showed weak antibacterial activity against limited number of tested bacteria. The current results showed that the essential oils of C. erythraeumand E. tenuifolia can be used in food preservation.

Two new naphthoquinones, named 12-hydroxy-naphthgeranine A (1) and isonaphthgeranine C (2) together with naphthgeranine A (3), were isolated from the cultures of Stereospermum’s rhizosphere strain Streptomyces sp. XZYN-4. Their structure were established on the basis of 1D, 2D-NMR experiments and HR QTOF MS. The absolute configurations of C-12 (12R ) in both (1) and (2) are different from those reported in naphthgeranine family. C ompounds 1 and 3 showed moderate activity against Aspergillus niger ACCC30005 by disk diffusion test at a dose of 20 m g/disk.

The flowers of Maackia fauriei have traditionally been used to treat hypertension, apoplexy, hemostasis, vaginal bleeding, and dystocia; moreover, the bark of this plant has been used as a natural dye. In the present study, activity-guided isolation of the leaves of M. fauriei yielded five isoflavones [genistein (1), pratensein (2), genistin (3), 2'-hydroxygenistein-7-O-β-D-glucopyranoside (4), and 2,3-dehydrokievitone (5)]; three pterocarpans [medicarpin (6), maackiain (7), and 4-hydroxy maackiain (8)]; and one flavonol [isoquercitrin (9)]. To evaluate the anti-oxidative effects of these compounds, their 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assays and nitrotetrazolium blue chloride (NBT) superoxide scavenging assays were measured. And the anti-tumor activity against human cancer cell lines in genital system, LNCaP, PC-3,HeLa and OVCAR-3 cells were evaluated by MTT method. Furthermore, the apoptosis of the PC-3 and HeLa cells were determined by by annexin V-FITC and PI their fluorescence was analyzed by flow cytometry. The flavonol (9, isoquercitrin) and pterocarpan (8, 4-hydroxymaackiain) showed strong anti-oxidative activities. Besides, the isoflavones (1-5) did not showed anti-oxidative activity and the isoflavones (1-5) and pterocarpans (6-8) generally showed the potent cytotoxic activity against all of four human genital cancer cells. Especially, 2,3-dehydrokievitone (5) which had a prenyl group at C-8 position of the A-ring exhibited strong cytotoxic activity and induced apoptosis efficiently in cancer cells.

Vitex negundo L., commonly known as the ‘Nirgundi’ has a long history of medicinal use in traditional and folk medicines for various diseases. To explore the diversity of the essential oil yield and composition of V. negundo, 23 populations were collected during spring season from the western Himalayan region . The essential oil yields varied from 0.06 to 0.10% in different populations of V. negundo. GC-FID, GC-MS, and statistical analysis of the leaf volatile oils showed significant phytochemical diversity. The volatiles of V. negundo were complex mixtures of 61 constituents, with sabinene (2.8-40.8%), viridiflorol (10.7%-23.8%), β-caryophyllene (5.3-21.4%), terpinen-4-ol (0.1-7.2%), epi-laurenene (2.2-5.9%), humulene epoxide II (0.5-4.6%), and abietadiene (0.1%-4.3%) as major constituents. Based on the distribution of major constituents, four groups were noticed by the multidimensional scaling and hierarchical average linkage cluster analyses. In conclusion, the yield and composition of the essential oils isolated from V. negundo varied considerably, depending on the origin.

Two new prenylated stilbenes with an irregular sesquiterpenyl side chain, solomonin B (1) and solomonin C (2), together with four known compounds, glyasperin A (3), isolated for the first time from propolis, kumatakenin (4), macarangin (5) and mangiferolic acid (6) were isolated from ethanol extract of propolis from Fiji islands. The compounds structures were determined based on their spectral data analysis (1D- and 2D NMR, UV and HREIMS) and comparison with literature data. The chemical composition of propolis from Fiji islands was determined for the first time.

Piper rivinoides is a Brazilian Piperaceae species of a little research from a chemical and biological point of view. The crude hydroalcoholic extract from leaves, the n-hexane fraction and pure isolated compounds from the leaves were evaluated against two strains of Candida albicans as well as Leishmania amazonensis and L. chagasi. Bioguided purification of the n-hexane fraction lead to isolation and chemical characterization of a mixture of two benzofuran neolignans, 2-(4’-methoxyphenyl)-3-methyl-5-(E)-propenylbenzofuran (1) and eupomatenoid-3 (2) as well as the pure compounds: eupomatenoid-5 (3), (2R,3R)-2,3-dihydro-2-(4’-hydroxy-3’-methoxyphenyl)-3-methyl-5(E)-propenylbenzofuran (4), eupomatenoid-6 (5) and conocarpan (6). The first approach in quantification found with basis on quantitative nuclear magnetic resonance showed that the n-hexane fraction contains about 29.8% of eupomatenoid-5 (3), 7.6% of eupomatenoid-6 (5) and 5.5% of conocarpan (6). The biological results showed conocarpan as the most active compound with less cytotoxicity than the other tested compounds. Our results suggest conocarpan as owner of the best scaffold model of the four neolignans tested for new promising antimicrobial agents against the tested parasites. The high content of neolignans in the n-hexane fraction stands out P. rivinoides as an important source of bioactive neolignans.

The principal components of essential oils, obtained by steam-hydrodistillation from the fresh leaves of five species of the genus Lippia, namely Lippia gracilis AV, Lippia sidoides Mart , Lippia alba carvoneifera, Lippia alba citralifera and Lippia alba myrceneifera and ethanol extracts , were evaluated. The greater antioxidant capacity (IC 50 = 980 µg/mL; p < 0.05), assessed by the HPLC-based hypoxanthine/xanthine oxidase assay, was determined in the essential oil obtained from Lippia alba carvoneifera, while the remainder were comparatively inactive (IC 50 > 2000 µg/mL). Major compounds in the oils were, thymol (Lippia sidoides Mart, 13.1 g/k), carvone (Lippia alba carvoneifera, 9.6 g/kg), geranial ( Lippia alba citraleifera, 4.61 g/kg; Lippiaalba myrceneifera, 1.6 g/kg), neral ( Lippia alba citraleifera, 3.4 g/kg; Lippia alba myrceneifera, 1.16 g/k), carvacrol (Lippia gracilis AV, 5.36 g/kg) and limonene (Lippia alba carvoneifera, 5.14 g/kg). Of these, carvone (IC 50 = 330 µM) along with thymol (1.88 units), and carvacrol (1.74) units, were highly active in the hypoxanthine/xanthine oxidase, and ORAC assays respectively. The following compounds namely I: calceolarioside E, II: acteoside, III: isoacteoside, IV: luteolin, V: 5,7,3´,4´-tetrahydroxy-3,6-dimethoxy flavone (spinacetin) , VI: naringenin, VII: apigenin, VIII: 6-methoxy apigenin (hispidulin), IX: 5,7,3´-trihydroxy-3,6,4´-trimethoxy flavone , X:5,7,4´-trihydroxy-3,6-dimethoxy flavone , XI: naringenin-4´-methyl ether, XII: 5,7-dihydroxy-3,6,4´-trimethoxy flavone (santin) , XIII:5,7-dihydroxy-6,4´-dimethoxy-flavone (pectolinaringenin) and XIV: 5-hydroxy-3,7,4´-trimethoxy flavone were identified in the ethanol extracts . Of the leaf ethanol extracts, strong antioxidant capacity was only evident in that of Lippia alba carvoneifera (IC 50 = 1.23 mg/mL). Overall, the data indicates that use of the leaves of Lippia species in food preparations, should be beneficial to health.

In this study, a solid phase micro extraction (SPME) method with gas chromatography-mass spectrometry (GC-MS) was used for analysis of volatile compounds in flowers and bulbs of three Ornithogalum species. The samples of flowers and bulbs of Ornithogalum sigmoideum, Ornithogalum orthophyllum, Ornithogalum oligophyllum was separately analyzed by SPME-GC-MS. A comparison of volatile compounds was made between species and the parts studied. A total of 70 compounds were identified and different volatile compounds were determined in distinct parts of the species. The major volatile organic compound of the flowers of O. sigmoideum and O. ornithogalum was furan (54.5% and 57.0% respectively). For O. oligophyllum the major volatile organic compound was nonanal (19.2%). Analyses revealed that SPME-GC-MS method is appropriate for the analysis of volatile compounds of Ornithogalum species

The chemical composition of the essential oil from the aerial parts of Thymus haussknechtii Velen. was analyzed by using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The major component of the essential oil was thymol (52.2%). Total phenolic content of the essential oil was determined as 132.9 µg gallic acid equivalent. The antioxidant capacity was evaluated by DPPH free radical, superoxide anion radical and hydrogen peroxide scavenging activities along with ferrous ion-chelating power test, ABTS radical cation decolorization assay and ferric thiocyanate methods. In addition to antioxidant activity, anticholinesterase activity of the essential oil was also evaluated. It exhibited inhibitory activities on AChE and BuChE which play an important role in Alzheimer’s disease, along with significant antioxidant activity.

A new epicatechin derivative, alchornealaxine (1), was isolated along with nine known compounds, hyperoside, reynoutrin, guaijaverin, taxifolin-3-O-β-D-galactopyranoside, taxifolin-3-O-β-D-xylopyranoside, byzantionoside B, leeaoside, syringaresinol-β-D-glucoside and β-sitosterol-β-D-glucoside from the leaves of Alchornea laxiflora. The structures of these compounds were determined on the basis of spectroscopic methods as well as HR-ESI-TOF-MS analysis. 

Chemical constituents and acetylcholinesterase inhibition was investigated in both essential oil and dichloromethane subextract obtained from the aerial parts of Senecio ventanensis, an endemic Asteraceae. The chemical composition of the oil was determined by GC and GC-MS. The major constituents were a -terpinene (12.2%), limonene (11.9%), -humulene (10.5%), sabinene (9.1%), terpinolene (8.8%), p-cymene (8.1%) and a -ocimene (7.3%). The bioassay guided isolation of the constituents of the active dichloromethane subextract (IC 50 = 361.6 µg/mL) led us to the isolation of two diastereoisomers of a sesquiterpene endoperoxide 3,6-epidioxy-1,10-bisaboladiene (1 and 2), reported here for the first time in S. ventanensis. The identification was achieved by comprehensive analyses of its 1H and 13C NMR spectroscopic data (including 2D experiments) and mass spectrometric data. Their absolute configuration is proposed on the basis of AM1 calculations and NOESY experiments. This is the first time that compounds 1 and 2 have been separated as well as the first phytochemical investigation of S. ventanensis.

Scrophularia amplexicaulis Benth. is an Iranian endemic species of the genus Scrophularia, which comprises ca. 200 medicinally important herbaceous flowering plants . Phytochemical investigation of the methanol extract of the aerial parts of this species afforded two iridoid glycosides, scropolioside D (1) and scrophuloside B 4 (2), and two phenylalkanoid glycosides, salidroside (3) and verbascoside (4). S tructures of these compounds were determined by comprehensive spectroscopic analyses. Free-radical-scavenging activity, potential antimalarial property, and contact toxicity as well as general toxicity of the extract and fractions were assessed.

The ethanol extract of Cynanchum ascyrifolium Matsum. showed significant anti-inflammatory and immunosuppressive activities with dose dependent manner using in vitro experiments. Then, the bioassay-guided ethanol extract lead to identification of four active compounds, namely ursolic acid (1), maslinic acid (2), cynanoside A (3) and syringaresinol (4). Among these compounds, cynanoside A (3), a C21 steroid, exhibited the highest anti-inflammatory and immunosuppressive effect on the Con-A or LPS activated lymphocytes at the concentration of 1 m M (P<0.01 vs model group). The results provided experimental evidence for the traditional use of C. ascyrifolium Matsum. in treating various disease associated with inflammation.